Introduction to common fire control systems in alarm data centers (1)

In July April, the machine room of Shanghai Telecom building ignited the heat preservation foam due to maintenance workers cutting the central air-conditioning duct, and once again sounded the Fire Safety alarm of the data center. Fire in or near the data processing equipment may cause equipment faults or damage. Smoke pollution may also lead to future faults, business interruptions, service interruptions, damage to customer reputation, damage to buildings or other physical structures. Therefore, the data center should first implement "prevention-based, fire-based combination", and put the fire in the air before the fire starts. BKJIA is recommended to read: internal and external causes of data center fire ).

As a system project, data centers must coordinate subsystems to play their roles normally. As a data center security protection subsystem, the fire protection system must support the overall functions of the data center. On the other hand, the fire protection support function must be coordinated by other subsystems of the data center. Therefore, the actual fire control system must be further integrated with the overall system design of the data center. This article briefly introduces the fire control systems commonly used in the data center.

I. Gas Extinguishing System

Gas extinguishing systems are widely used for the protection of important equipment rooms. The system features no obvious damage to the device, and the system is relatively simple and flexible.

The gas extinguishing system can be divided into chemical gas extinguishing agent and inert gas extinguishing agent. The principle of chemical gas fire extinguishing agent is that the fire extinguishing agent participates in the combustion process and cut off the combustion chain reaction. The typical chemical gas fire extinguishing agent is PTFE propane, which has the advantage of high fire extinguishing efficiency, especially for oil. However, most of these gases are super greenhouse gases, so they should not be used in large quantities. In addition, chemical gases in the fire extinguishing process, in the high temperature environment will also decomposition of hydrofluoric acid and other by-products, while hydrofluoric acid is very corrosive, will slowly corrode electronic equipment.

The principle of the inert fire extinguishing agent is to reduce the oxygen concentration in the protected area so that it cannot support combustion, which is completely different from the chemical gas fire extinguishing agent. The typical inert fire extinguishing agent is IG-541, which is a mixture of nitrogen, argon and carbon dioxide. For data centers, the fire suppression concentration of inert gases is many times higher than that of chemical gases, so there are many cylinders, occupying a large area between cylinders, but the fire extinguishing agent is cheap, the overall cost is slightly higher than that of the chemical gas fire extinguishing system.

Clean gas is the definition in 1996 NEPA2001, that is, the gas fire extinguishing agent that is not conductive, volatile, and residual in evaporation. A clean gas is a concept targeting halon 1301 or 1211, that is, a gas that has no damage to the atmospheric ozone layer. It is a clean gas, but it is not a "green" Environmentally Friendly gas.

The use of the gas extinguishing system should fully take into account the characteristics of the system. Gas extinguishing systems are used in small data centers and should not be transported over long distances. If the protected area is too large, it will make it difficult for the fire extinguishing agent to reach the specified fire extinguishing concentration, and it is very economic.

The gas fire extinguishing system has strict requirements on the sealing of the protected area, and it is difficult to strictly "seal" it in actual engineering ". According to the us fm survey, the failure rate of gas fire suppression is 49%, and most of the failure is caused by the failure of the fire extinguishing agent to reach the designed fire suppression concentration. So far, there have been no successful gas suppression cases in China. In addition, gas fire suppression systems are often sprayed incorrectly in and outside China, and even wounding incidents occur. Therefore, in consideration of safety, the gas fire extinguishing system shall not be used in a dedicated IDC.